It's not about the bike

I'm about to commit adultery -- yes, I'm looking for a sports bike, not to take part in the upcoming Tour de France, you understand, but in order to improve my running time.  Biking, apparently, boosts 5k and 10k performance times, a concept that is a hard pill to swallow for a runner.  Most runners regard any time spent doing another sport as a wasteful distraction from the main event, but I thought the time was ripe for a bit of sporting infidelity.